Analysis of type 1 fimbriae expression in verotoxigenic Escherichia coli: a comparison between serotypes O157 and O26

• Published in: Microbiology (Society for General Microbiology) 2001-01, Vol.147 (1), p.145-152
• Main Authors: Roe, Andrew J, Currie, Carol, Smith, David G. E, Gally, David L
• Format: Article
• Language: English
• Subjects: Animals; Bacterial Adhesion; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacteriology; Base Sequence; Biological and medical sciences; Cattle; Cloning, Molecular; Escherichia coli - classification; Escherichia coli - genetics; Escherichia coli - growth & development; Escherichia coli - metabolism; Escherichia coli O157 - genetics; Escherichia coli O157 - growth & development; Escherichia coli O157 - metabolism; Fimbriae Proteins; Fundamental and applied biological sciences. Psychology; Gene Deletion; Gene Expression Regulation, Bacterial; Genetics; Humans; Microbiology; Molecular Sequence Data; Sequence Analysis, DNA; Serotyping; Shiga Toxins - metabolism
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/00221287-147-1-145

Zoonotic and Animal Pathogens Research Laboratory, Medical Microbiology, Teviot Place, University of Edinburgh, Edinburgh EH8 9AG, UK 1 Author for correspondence: David Gally. Tel: [phone]. Fax: [phone]. e-mail: d.gally{at}ed.ac.uk Previous research has shown that verotoxin-producing Escherichia coli (VTEC) O157 strains appear unable to express type 1 fimbriae although other serotypes such as O26 and O118 can. This study has investigated the molecular basis of this difference. The study confirmed the presence of a 16 bp deletion within the regulatory region of fimA ( fim switch) in 63 VTEC O157 strains but not in other VTEC serotypes tested. The fim switch was shown to be detectable only in the phase off orientation in VTEC O157, but detection of the switch in the phase on orientation correlated with the degree of mannose-sensitive yeast agglutination in VTEC O26. Repair of the 16 bp deletion in the VTEC O157 fim switch region restored phase-variable expression of fimA in a permissive background. Non-O157 VTEC, especially O26 and O118, can be pathogenic in cattle; the role of type 1 fimbriae in this and colonization is discussed. Keywords: Escherichia coli O157, VTEC, type 1 fimbriae, phase variation, adherence Abbreviations: A/E, attaching and effacing; IHF, integration host factor; VTEC, verotoxigenic E. coli